While today, December 21st, 2021 is referred to as the winter solstice, the solstice is actually the precise moment when the earth’s north pole is tipped the furthest away from the sun and that occurred this morning at 7:58 am PST. This marks the start of winter and the day in which we’ll get the fewest hours of sunlight and the longest night.
Every year people gather at Stonehenge, in England on the first day after the solstice to view the sunrise on the day when the days start to become longer (more sunlight). You can watch coverage starting at 12:09 am on 12/22/21, (also a six-digit palindrome date!).
In the solar industry, we pay close attention to the sun. We do calculations of roof pitch, orientation, shading and solar exposure to calculate the efficiencies and production of solar photovoltaic systems. These calculations are complex as the sun’s trajectory in our sky changes so dramatically over the course of the year here in the Pacific Northwest. On the winter solstice, the sun is only in our sky for 8 hours and 25 minute and it’s at 19 degrees on the horizon at solar noon. On the summer solstice, we get 15 hours and 59 minutes of sunlight and the sun is at 66 degrees at solar noon. The difference is 7 hours and 34 more minutes of sunlight.
That’s a huge difference. We get 74% of our sunlight over a six month period between March 21st and September 21st. This is one reason why Net Metering is important for homeowners and businesses with solar PV in northern latitudes.
Also, solar electric panels generate more power when they are cooler, so even though Seattle gets 70% of the sun that Los Angeles does, a solar panel here will produce 80% of what it will in L.A. over the course of a year.
Two years ago, here in Seattle, we experienced the darkest day on record on 12/20/19, the day before the winter solstice because we were getting hammered with rain from an atmospheric river, allowing little sunlight through the clouds an rain.
So, while today’s not a great day for solar production, (but way better than 12/20/19!!!), it is a great time to get a free custom quote as the days are starting to get longer and so you’re on our installation calendar and ready to go when the high production days of March to September arrive.
Give us a call at 206-706-1931 or fill out our contact form for your customized solar quote.